The thing that differentiates sfz from soundfonts is that with sfz, the samples aren't integrated into the performance file so any number of sfz files can use the same samples as long as the player knows where to look for the samples. That means you can create thousands of VSTi/standalone instruments. The old Cakewalk sfz player full version could create unlimited layers and had live controls on the GUI. but that is no longer available

Here is a page with a link to a directory from which I just got 3 sfz players. one DLL and EXE. Now, one of these is called sfz197. In a later post a person mentions that the Cakewalk unit was the sfz 1.9.7 which last version I saw was the rgaudio sfz player. This was in fact a downgraded version since, at the time, the full version was a paid version from Cakewalk. The Full version had a gorgeous GUI with lots of fader controls and could support unlimited layering. the rgaudio could support 2 layers and had not much of a GUI at all

This is an old program so whether it will work today, I do not know, but here's the link to the forum that will get you the link to the directory I just downoaded from